Remember that the only purpose of JSP is to format an HTML page for sending to the client. Anything you can do with HTML/JavaScript you can do in the JSP. Conversely, there's no magic that lets you do things beyond the capabilities built into the browsers. hth, bear

Thank you for your answer. Anyway, I haven't understood it yet. For example, I can use window.open() in javascript to open a new window, and resize it, define its properties. But when I use response.sendRedirect("a.jsp") in a JSP page and jump into the "a.jsp" page. I mean how to code in a.jsp to resize the current window, such as hiding the toolbar, defining the window's height and width, no matter we use javascript or Jsp? Or there is no way to do it?

JSP is a server-side technology that merely allows you to easily generate what will be sent to the client side. There is nothing in JSP that will allow you to control anything on the client -- merely to help you format the HTML and JavaScript that will be sent there. You must use HTML or JavaScript technologies to control your client; e.g. window.open(), window.resizeTo() and so on. hth, bear